I would suggest the same. I have t-shirts, hoodies, and very few sleeveless tops (I'm not a fan). Other than that, Kaji will be getting jerseys this year. It's really not that exciting for the boys.
PetCo when they're having a sale is good. So does PetSmart. But... and there is a big but, if your little one fits PetSmart clothing in length, he won't fit PetCo clothes. If he fits PetCo, he won't fit PetSmart. It sucks, but that's the way it is. Kaji is a PetCo boy. The length is perfect on the back, and on the tummy. (no accidental pee pee on the shirt) Whereas PetSmart shirts are too long, and one size down and it's a crop top.
It's really sad since PetSmart is starting to have such fun short sleeved tees for boys. * NERD ALERT* I love the Marvel tees, but they don't fit Kaji.
Old Navy use to have awesome quality items for a reasonable price. They stopped making boy clothes too.
Sometimes boutiques have cute stuff... but that's usually pricier. I'm willing to spend $$ on a good jacket, or a cute sweater. But I found that the $8 jacket I got at Ross is the one that gets the most use.
I've also used baby tees and onesies to make Kaji clothes. I'm by no means a seamstress. I don't even own a sewing machine, but they turn out well. There's a how to I made for this forum a long time ago if you're interested in checking that out.
Sorry for going on and on! I love dressing up Kaji, and having cute options for him.